| 摘要 |
PURPOSE:To easily and quickly execute a backup at the time of a fault by a simple constitution, by storing in advance the minimum processing contents of other controller required for the time of a backup, in respective (n+k) pieces of controller. CONSTITUTION:By limiting the processing contents stored in a backup controller 5 to the processing contents of a controller 6 of a plural pieces portion, a backup of (n):(k) (1<=k<=n) can be executed, therefore, as for the processing contents for a backup, a small quantity is enough, and accordingly, as for all the controllers to be used, inexpensive one of the same kind of machine can be used. Because of a homogeneous system constitution, there is no common mode, and the system abounds in the extendability. Also, even at the time of a backup of (n):(k), the dispersibility of the system is secured. Moreover, since an output is selected between plural processing contents stored in advance in the controller, there is not time delay at the time of executing down-loading from a host computer to a low-order backup controller, and it becomes possible to cope quickly with a fault. |
